Ramblings of a network engineer

Wednesday 14 December 2016

CCIE RS Revision Series - Regexp Review & how to grep Cisco

I learn regular expressions, I forget regular expressions. I learn regular expressions, I forget regular expressions. Sound familiar?

Some of this stuff sticks for a while, but the devil is in the details & if like me you rarely use them in your day to day, well the information just evaporates out of your ears.

Typically if you are a non Linux/Unix fellow, then your regexp usage would come from BGP. If you are not a regular user of BGP then how else can one make use of these tools?

There is another way you can get more out of regular expressions & use them in your day to day therefore helping you to commit this info to long term memory. What i am talking about is the grep functionality of Cisco IOS (tested in IOS & XE).

R10#conf t
R10(config)#shell processing full

This allows us to call on the grep functionality to search within output, lets use this to look for an IP address within our configuration:

R10#show run | grep [0-9]*\\.[0-9]*\\.[0-9]*\\.[0-9]*
ip address 150.1.10.10 255.255.255.255
ip address 172.16.5.6 255.255.255.0
ip igmp join-group 225.1.2.3
ip address 155.1.10.10 255.255.255.0

From this we can see the grep functionality has worked, lets breakdown what exactly we did to glean this information:

First off we have set a criteria of a range from 0-9 within the square brackets [0-9], here we are saying any value from 0-9.
Next up is the *, this special character matches zero or more occurrences of the preceding character. Therefore we would match nothing ' ', one single character '1' or '3' & also multiple numerical characters '123' or '222'.
The next character's, the double \\ tells grep that the dot '.' that follows the \\ is to interpreted as a literal dot, not a special character (the dot would otherwise mean match any single character including a blank space)

The above pattern is repeated 4 times, to look for four sets of numerical values that are separated by a dot. Which is what makes up an IPv4 address.

Lets quickly talk about why we need the double backslash before we move on, first lets look at what the CLI interprets these as by way of echo:

R10#echo \

R10#echo \\

R10#echo '\'

R10#echo '\\'

R10#echo \.

R10#echo \\.

As you can see if we exclude single quotations ' ' then the \ has special meaning to the parser & is not displayed. What is interesting & I don't yet know the answer is, why do i need a double \\ to make the dot appear in its true form, when the echo above shows that only a single slash is needed to parse the following data correctly. I would expect my IPv4 regexp to interpret the second slash as literal as per the final echo output.

What I understand is that the \ is also a shell quoting character & hard to use as an escape character, thereby double \\ may be needed for grep but not for the echo command.

To avoid the double \\, you can just put your expression inside of single quotes ' ' & use a single slash \

R10#show run | grep '[0-9]*\.[0-9]*\.[0-9]*\.[0-9]*'

ip domain name 1a.23.45.6

ip address 150.1.10.10 255.255.255.255

ip address 192.168.0.1 255.255.255.0

ip address 172.16.5.6 255.255.255.0

ip igmp join-group 225.1.2.3

ip address 155.1.10.10 255.255.255.0

ip address 155.1.108.10 255.255.255.0

You may noticed I have added a domain name that looks somewhat like an IP address. However we do not want to match on this, but the reason we are is due to the * in the search, whereby the * matches zero or more occurrences of the preceding character. In this case the domain name is matched by the zero value, as the character before the first dot '.' can be numerical or nothing (zero).

To fix this we substitute the * with a +, where the + sign indicates that we much match one or more of the preceding values. Meaning there must be a numerical value before the dot '.'.

R10#show run | grep '[0-9]+\.[0-9]+\.[0-9]+\.[0-9]+'

ip address 150.1.10.10 255.255.255.255

ip address 192.168.0.1 255.255.255.0

ip address 172.16.5.6 255.255.255.0

ip igmp join-group 225.1.2.3

ip address 155.1.10.10 255.255.255.0

ip address 155.1.108.10 255.255.255.0

However if we now modify the domain name to 'bib127.0.0.1', we should match it again as the character preceding the first dot '.' is numerical.

R10#show run | grep '[0-9]+\.[0-9]+\.[0-9]+\.[0-9]+'

ip domain name bib127.0.0.1

ip address 150.1.10.10 255.255.255.255

ip address 192.168.0.1 255.255.255.0

ip address 172.16.5.6 255.255.255.0

ip igmp join-group 225.1.2.3

ip address 155.1.10.10 255.255.255.0

ip address 155.1.108.10 255.255.255.0

We know that in our example there is a leading white space, therefore we can add this into out filter to remove the unwanted results, here are both methods:

R10#show run | grep ' [0-9]+\.[0-9]+\.[0-9]+\.[0-9]+'

R10#show run | grep \ [0-9]+\\.[0-9]+\\.[0-9]+\\.[0-9]+

ip address 150.1.10.10 255.255.255.255

ip address 192.168.0.1 255.255.255.0

ip address 172.16.5.6 255.255.255.0

ip igmp join-group 225.1.2.3

ip address 155.1.10.10 255.255.255.0

ip address 155.1.108.10 255.255.255.0

We do have the _ underscore to match on white space, but testing has shown this not to work with grep, however it does work with regexp for searching the BGP tables.

As you can see the grep feature can be used as part of your day to day, try swapping out the 'include' & 'section' searches & use grep instead, your future self will thank you for it!

Now finally by way of example, here are some regexp's I have taken from my notes and the results they would yield:

^100:1_ Match 100:1 at the start of the line
200:3$ Match 200:3 at the end of the line
300:[5-9]_ Match a range from 300:5 to 300:9 the _ signifies the end so only 1 digit allowed after the :
400:1.*_ Matches 400:1XXXX where X is anything as the . means any character & the * means the previous match the previous charterer 0 or more times.
400:1.+_ is as previous, but wont match 400:1 as the + means 1 or more times, so a second character is needed.
500:([0-9]2)+_ inside the ( ) is treated as one expression where the + means this expression must be there 1 or more times, so 500:X2 & 500:X2X2X2 all match.
600:1_ | 600:2_ is using a | alternate, which looks for either of the patterns
600:(12)|(22) uses the | OR to look for 600:12 or 600:22

Saturday 10 December 2016

CCIE RS Revision Series - Diagnostics Sample Question 1

Diagnostics Sample Question:

Your job is to diagnose & locate the source of the problem, please post your comments below & I will follow this up with a post detailing the solution in due course.

:::

The following is the topology for BlogTown's new network that has just been installed. It is made up of three multilayer switches. The core switch 'Switch 2' provides layer three access to various services, such as the Internet & internal servers.

The two clients that connected to Switch 1 & Switch 3 are both in the same VLAN & subnet '192.168.1.0/24'

Reported issue:

The users of the clients have complained that they cannot communicate directly with one another.

Troubleshooting already completed:

Ping tests were run from both client PC's to test reachability. Following this a second ping test was run to see if either client could reach the Internet facing port Eth1/1 on Switch 2, results can be seen below in the log file 'Initial Pings".

Further Information Requested:

To help isolate the fault the following items were asked for & can be seen below:

-"show run" from all three switches

-"show vtp status" from all three switches

-"show vlan" from switches 1 & 3

-"show spanning-tree" from switch 1

-"show log" from switch 2

Initial Pings:

CLIENT1#ping 192.168.1.1

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 192.168.1.1, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 5/5/5 ms

CLIENT1#ping 192.168.1.2

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 192.168.1.2, timeout is 2 seconds:

.....

Success rate is 0 percent (0/5)

CLIENT1#ping 192.168.255.2

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 192.168.255.2, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/1 ms

CLIENT2#ping 192.168.1.2

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 192.168.1.2, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 4/4/5 ms

CLIENT2#ping 192.168.1.1

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 192.168.1.1, timeout is 2 seconds:

.....

Success rate is 0 percent (0/5)

CLIENT2#ping 192.168.255.2

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 192.168.255.2, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/1 ms

Show Command outputs

!!!!Switch 1

SW1#show run

Building configuration...

Current configuration : 1469 bytes

! Last configuration change at 04:01:14 CST Sat Nov 5 2016

version 15.2

service timestamps debug datetime msec

service timestamps log datetime msec

no service password-encryption

service compress-config

hostname SW1

boot-start-marker

boot-end-marker

enable password cisco

no aaa new-model

clock timezone CST -6 0

no ip domain-lookup

ip cef

ipv6 multicast rpf use-bgp

no ipv6 cef

spanning-tree mode pvst

spanning-tree extend system-id

vlan internal allocation policy ascending

interface Ethernet0/0

switchport mode dynamic desirable

shutdown

interface Ethernet0/1

switchport mode dynamic desirable

shutdown

interface Ethernet0/2

switchport access vlan 1008

switchport mode access

interface Ethernet0/3

switchport mode dynamic desirable

shutdown

interface Ethernet1/0

switchport trunk encapsulation dot1q

switchport mode trunk

interface Ethernet1/1

switchport mode dynamic desirable

shutdown

interface Ethernet1/2

switchport mode dynamic desirable

shutdown

interface Ethernet1/3

switchport mode dynamic desirable

shutdown

interface Vlan1

ip address 192.168.0.1 255.255.255.0

ip ospf 1 area 0

interface Vlan1008

ip address 192.168.1.11 255.255.255.0

ip ospf 1 area 0

router ospf 1

ip forward-protocol nd

no ip http server

no ip http secure-server

control-plane

line con 0

logging synchronous

line aux 0

line vty 0 4

password cisco

end

SW1#show vtp status

VTP Version capable : 1 to 3

VTP version running : 3

VTP Domain Name : CISCO

VTP Pruning Mode : Disabled

VTP Traps Generation : Disabled

Device ID : aabb.cc00.6500

Feature VLAN:

--------------

VTP Operating Mode : Primary Server

Number of existing VLANs : 9

Number of existing extended VLANs : 1

Maximum VLANs supported locally : 4096

Configuration Revision : 4

Primary ID : aabb.cc00.6500

Primary Description : SW1

MD5 digest : 0xE5 0x6D 0x8F 0x0B 0x12 0x2E 0xF7 0xF1

0x48 0xE9 0xF6 0x57 0x27 0x93 0x1E 0xB4

Feature MST:

--------------

VTP Operating Mode : Transparent

Feature UNKNOWN:

--------------

VTP Operating Mode : Transparent

SW1#show vlan

VLAN Name Status Ports

---- -------------------------------- --------- -------------------------------

1 default active Et0/0, Et0/1, Et0/3, Et1/1

Et1/2, Et1/3

2 VLAN0002 active

5 VLAN0005 active

55 VLAN0055 active

66 VLAN0066 active

1002 fddi-default act/unsup

1003 trcrf-default act/unsup

1004 fddinet-default act/unsup

1005 trbrf-default act/unsup

1008 VLAN1008 active Et0/2

VLAN Type SAID MTU Parent RingNo BridgeNo Stp BrdgMode Trans1 Trans2

---- ----- ---------- ----- ------ ------ -------- ---- -------- ------ ------

1 enet 100001 1500 - - - - - 0 0

2 enet 100002 1500 - - - - - 0 0

5 enet 100005 1500 - - - - - 0 0

55 enet 100055 1500 - - - - - 0 0

66 enet 100066 1500 - - - - - 0 0

1002 fddi 101002 1500 - - - - - 0 0

VLAN Type SAID MTU Parent RingNo BridgeNo Stp BrdgMode Trans1 Trans2

---- ----- ---------- ----- ------ ------ -------- ---- -------- ------ ------

1003 trcrf 101003 4472 1005 3276 - - srb 0 0

1004 fdnet 101004 1500 - - - ieee - 0 0

1005 trbrf 101005 4472 - - 15 ibm - 0 0

1008 enet 101008 1500 - - - - - 0 0

VLAN AREHops STEHops Backup CRF

---- ------- ------- ----------

1003 7 7 off

Primary Secondary Type Ports

------- --------- ----------------- ------------------------------------------

SW1#show spanning-tree

VLAN0001

Spanning tree enabled protocol ieee

Root ID Priority 32769

Address aabb.cc00.6500

This bridge is the root

Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 32769 (priority 32768 sys-id-ext 1)

Address aabb.cc00.6500

Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Aging Time 300 sec

Interface Role Sts Cost Prio.Nbr Type

------------------- ---- --- --------- -------- --------------------------------

Et1/0 Desg FWD 100 128.5 Shr

VLAN0002

Spanning tree enabled protocol ieee

Root ID Priority 32770

Address aabb.cc00.6500

This bridge is the root

Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 32770 (priority 32768 sys-id-ext 2)

Address aabb.cc00.6500

Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Aging Time 300 sec

Interface Role Sts Cost Prio.Nbr Type

------------------- ---- --- --------- -------- --------------------------------

Et1/0 Desg FWD 100 128.5 Shr

VLAN0005

Spanning tree enabled protocol ieee

Root ID Priority 32773

Address aabb.cc00.6500

This bridge is the root

Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 32773 (priority 32768 sys-id-ext 5)

Address aabb.cc00.6500

Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Aging Time 300 sec

Interface Role Sts Cost Prio.Nbr Type

------------------- ---- --- --------- -------- --------------------------------

Et1/0 Desg FWD 100 128.5 Shr

VLAN0055

Spanning tree enabled protocol ieee

Root ID Priority 32823

Address aabb.cc00.6500

This bridge is the root

Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 32823 (priority 32768 sys-id-ext 55)

Address aabb.cc00.6500

Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Aging Time 300 sec

Interface Role Sts Cost Prio.Nbr Type

------------------- ---- --- --------- -------- --------------------------------

Et1/0 Desg FWD 100 128.5 Shr

VLAN0066

Spanning tree enabled protocol ieee

Root ID Priority 32834

Address aabb.cc00.6500

This bridge is the root

Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 32834 (priority 32768 sys-id-ext 66)

Address aabb.cc00.6500

Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Aging Time 300 sec

Interface Role Sts Cost Prio.Nbr Type

------------------- ---- --- --------- -------- --------------------------------

Et1/0 Desg FWD 100 128.5 Shr

VLAN1008

Spanning tree enabled protocol ieee

Root ID Priority 33776

Address aabb.cc00.6500

This bridge is the root

Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 33776 (priority 32768 sys-id-ext 1008)

Address aabb.cc00.6500

Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Aging Time 300 sec

Interface Role Sts Cost Prio.Nbr Type

------------------- ---- --- --------- -------- --------------------------------

Et0/2 Desg FWD 100 128.3 Shr

Et1/0 Desg FWD 100 128.5 Shr

!!!!Switch 2

SW2#show run

Building configuration...

Current configuration : 1515 bytes

! Last configuration change at 04:03:56 CST Sat Nov 5 2016

version 15.2

service timestamps debug datetime msec

service timestamps log datetime msec

no service password-encryption

service compress-config

hostname SW2

boot-start-marker

boot-end-marker

enable password cisco

no aaa new-model

clock timezone CST -6 0

no ip domain-lookup

ip cef

ipv6 multicast rpf use-bgp

no ipv6 cef

spanning-tree mode pvst

spanning-tree extend system-id

vlan internal allocation policy ascending

interface Ethernet0/0

no switchport

ip address 192.168.23.2 255.255.255.0

duplex auto

interface Ethernet0/1

no switchport

ip address 192.168.24.2 255.255.255.0

duplex auto

interface Ethernet0/2

switchport trunk encapsulation dot1q

switchport mode trunk

interface Ethernet0/3

shutdown

interface Ethernet1/0

switchport trunk encapsulation dot1q

switchport mode trunk

interface Ethernet1/1

no switchport

ip address 192.168.255.2 255.255.255.0

duplex auto

interface Ethernet1/2

no switchport

ip address 192.168.25.2 255.255.255.0

duplex auto

interface Ethernet1/3

no switchport

ip address 192.168.26.2 255.255.255.0

duplex auto

interface Vlan1

ip address 192.168.0.2 255.255.255.0

ip ospf 1 area 0

router ospf 1

network 0.0.0.0 255.255.255.255 area 0

ip forward-protocol nd

no ip http server

no ip http secure-server

control-plane

line con 0

logging synchronous

line aux 0

line vty 0 4

password cisco

end

SW2#show vtp status

VTP Version capable : 1 to 3

VTP version running : 3

VTP Domain Name : CISCO

VTP Pruning Mode : Disabled

VTP Traps Generation : Disabled

Device ID : aabb.cc00.6600

Feature VLAN:

--------------

VTP Operating Mode : Client

Number of existing VLANs : 9

Number of existing extended VLANs : 0

Maximum VLANs supported locally : 4096

Configuration Revision : 4

Primary ID : aabb.cc00.6500

Primary Description : SW1

MD5 digest : 0xE5 0x6D 0x8F 0x0B 0x12 0x2E 0xF7 0xF1

0x48 0xE9 0xF6 0x57 0x27 0x93 0x1E 0xB4

Feature MST:

--------------

VTP Operating Mode : Transparent

Feature UNKNOWN:

--------------

VTP Operating Mode : Transparent

SW2#show log

*Nov 5 09:56:59.789: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan1, changed state to down

*Nov 5 09:57:52.203: %LINK-3-UPDOWN: Interface Vlan1, changed state to up

*Nov 5 09:57:53.210: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan1, changed state to up

*Nov 5 09:58:14.336: ICMP: echo reply sent, src 192.168.0.2, dst 192.168.0.1, topology BASE, dscp 0 topoid 0

*Nov 5 09:58:14.337: ICMP: echo reply sent, src 192.168.0.2, dst 192.168.0.1, topology BASE, dscp 0 topoid 0

*Nov 5 09:58:36.026: %OSPF-5-ADJCHG: Process 1, Nbr 192.168.0.1 on Vlan1 from LOADING to FULL, Loading Done

*Nov 5 09:58:39.008: %OSPF-5-ADJCHG: Process 1, Nbr 10.11.0.103 on Vlan1 from LOADING to FULL, Loading Done

*Nov 5 10:01:08.538: %LINK-5-CHANGED: Interface Loopback0, changed state to administratively down

*Nov 5 10:01:09.544: %LINEPROTO-5-UPDOWN: Line protocol on Interface Loopback0, changed state to down

*Nov 5 10:01:25.687: %SYS-5-CONFIG_I: Configured from console by console

*Nov 5 10:02:03.321: ICMP: echo reply sent, src 192.168.23.2, dst 192.168.1.1, topology BASE, dscp 0 topoid 0

*Nov 5 10:02:05.321: ICMP: echo reply sent, src 192.168.23.2, dst 192.168.1.1, topology BASE, dscp 0 topoid 0

*Nov 5 10:03:12.127: ICMP: echo reply sent, src 192.168.23.2, dst 192.168.1.1, topology BASE, dscp 0 topoid 0

*Nov 5 10:03:12.128: ICMP: echo reply sent, src 192.168.23.2, dst 192.168.1.1, topology BASE, dscp 0 topoid 0

*Nov 5 10:03:56.453: %SYS-5-CONFIG_I: Configured from console by console

*Nov 5 10:05:37.356: ICMP: echo reply sent, src 192.168.26.2, dst 192.168.1.1, topology BASE, dscp 0 topoid 0

*Nov 5 10:05:39.359: ICMP: echo reply sent, src 192.168.26.2, dst 192.168.1.1, topology BASE, dscp 0 topoid 0

*Nov 5 10:06:03.944: ICMP: echo reply sent, src 192.168.26.2, dst 192.168.1.2, topology BASE, dscp 0 topoid 0

*Nov 5 10:06:05.947: ICMP: echo reply sent, src 192.168.26.2, dst 192.168.1.2, topology BASE, dscp 0 topoid 0

*Nov 5 10:25:34.323: ICMP: echo reply sent, src 192.168.255.2, dst 192.168.1.1, topology BASE, dscp 0 topoid 0

*Nov 5 10:25:34.324: ICMP: echo reply sent, src 192.168.255.2, dst 192.168.1.1, topology BASE, dscp 0 topoid 0

*Nov 5 10:26:30.455: ICMP: echo reply sent, src 192.168.255.2, dst 192.168.1.2, topology BASE, dscp 0 topoid 0

*Nov 5 10:39:24.829: OSPF-1 ADJ Et0/0: Rcv pkt from 192.168.24.2, area 0.0.0.0 : src not on the same network

*Nov 5 10:39:31.234: OSPF-1 ADJ Et0/1: Rcv pkt from 192.168.23.2, area 0.0.0.0 : src not on the same network

*Nov 5 10:39:34.116: OSPF-1 ADJ Et0/0: Rcv pkt from 192.168.24.2, area 0.0.0.0 : src not on the same network

*Nov 5 10:39:40.977: OSPF-1 ADJ Et0/1: Rcv pkt from 192.168.23.2, area 0.0.0.0 : src not on the same network

*Nov 5 10:39:43.416: OSPF-1 ADJ Et0/0: Rcv pkt from 192.168.24.2, area 0.0.0.0 : src not on the same network

*Nov 5 10:39:50.317: OSPF-1 ADJ Et0/1: Rcv pkt from 192.168.23.2, area 0.0.0.0 : src not on the same network

*Nov 5 10:39:52.829: OSPF-1 ADJ Et0/0: Rcv pkt from 192.168.24.2, area 0.0.0.0 : src not on the same network

*Nov 5 10:40:00.058: OSPF-1 ADJ Et0/1: Rcv pkt from 192.168.23.2, area 0.0.0.0 : src not on the same network

*Nov 5 10:40:02.544: OSPF-1 ADJ Et0/0: Rcv pkt from 192.168.24.2, area 0.0.0.0 : src not on the same network

*Nov 5 10:40:07.017: ICMP: echo reply sent, src 192.168.255.2, dst 192.168.1.2, topology BASE, dscp 0 topoid 0

*Nov 5 10:40:07.022: ICMP: echo reply sent, src 192.168.255.2, dst 192.168.1.2, topology BASE, dscp 0 topoid 0

*Nov 5 10:40:07.027: ICMP: echo reply sent, src 192.168.255.2, dst 192.168.1.2, topology BASE, dscp 0 topoid 0

*Nov 5 10:40:07.032: ICMP: echo reply sent, src 192.168.255.2, dst 192.168.1.2, topology BASE, dscp 0 topoid 0

*Nov 5 10:40:07.036: ICMP: echo reply sent, src 192.168.255.2, dst 192.168.1.2, topology BASE, dscp 0 topoid 0

*Nov 5 10:40:09.162: OSPF-1 ADJ Et0/1: Rcv pkt from 192.168.23.2, area 0.0.0.0 : src not on the same network

*Nov 5 10:40:11.680: OSPF-1 ADJ Vl1: 192.168.0.1 address 192.168.0.1 is dead

*Nov 5 10:40:11.680: OSPF-1 ADJ Vl1: 192.168.0.1 address 192.168.0.1 is dead, state DOWN

*Nov 5 10:40:11.680: %OSPF-5-ADJCHG: Process 1, Nbr 192.168.0.1 on Vlan1 from FULL to DOWN, Neighbor Down: Dead timer expired

*Nov 5 10:40:11.680: OSPF-1 ADJ Vl1: Neighbor change event

*Nov 5 10:40:11.680: OSPF-1 ADJ Vl1: DR/BDR election

*Nov 5 10:40:11.680: OSPF-1 ADJ Vl1: Elect BDR 10.11.0.103

*Nov 5 10:40:11.680: OSPF-1 ADJ Vl1: Elect DR 10.11.0.103

*Nov 5 10:40:11.680: OSPF-1 ADJ Vl1: DR: 10.11.0.103 (Id)

*Nov 5 10:40:11.680: OSPF-1 ADJ Vl1: BDR: 10.11.0.103 (Id)

*Nov 5 10:40:11.680: OSPF-1 ADJ Vl1: Remember old DR 192.168.0.1 (id)

*Nov 5 10:40:12.126: OSPF-1 ADJ Et0/0: Rcv pkt from 192.168.24.2, area 0.0.0.0 : src not on the same network

*Nov 5 10:40:17.911: OSPF-1 ADJ Vl1: Neighbor change event

*Nov 5 10:40:17.911: OSPF-1 ADJ Vl1: DR/BDR election

*Nov 5 10:40:17.911: OSPF-1 ADJ Vl1: Elect BDR 10.11.0.102

*Nov 5 10:40:17.911: OSPF-1 ADJ Vl1: Elect DR 10.11.0.103

*Nov 5 10:40:17.911: OSPF-1 ADJ Vl1: Elect BDR 10.11.0.102

*Nov 5 10:40:17.911: OSPF-1 ADJ Vl1: Elect DR 10.11.0.103

*Nov 5 10:40:17.911: OSPF-1 ADJ Vl1: DR: 10.11.0.103 (Id)

*Nov 5 10:40:17.911: OSPF-1 ADJ Vl1: BDR: 10.11.0.102 (Id)

*Nov 5 10:40:17.911: OSPF-1 ADJ Vl1: Neighbor change event

*Nov 5 10:40:17.911: OSPF-1 ADJ Vl1: DR/BDR election

*Nov 5 10:40:17.911: OSPF-1 ADJ Vl1: Elect BDR 10.11.0.102

*Nov 5 10:40:17.911: OSPF-1 ADJ Vl1: Elect DR 10.11.0.103

*Nov 5 10:40:17.911: OSPF-1 ADJ Vl1: DR: 10.11.0.103 (Id)

*Nov 5 10:40:17.911: OSPF-1 ADJ Vl1: BDR: 10.11.0.102 (Id)

*Nov 5 10:40:18.672: OSPF-1 ADJ Et0/1: Rcv pkt from 192.168.23.2, area 0.0.0.0 : src not on the same network

*Nov 5 10:40:21.668: OSPF-1 ADJ Et0/0: Rcv pkt from 192.168.24.2, area 0.0.0.0 : src not on the same network

*Nov 5 10:40:24.550: %PM-4-EXT_VLAN_INUSE: VLAN 1008 currently in use by Ethernet1/2

*Nov 5 10:40:24.550: %SW_VLAN-4-VLAN_CREATE_FAIL: Failed to create VLANs 1008: VLAN(s) not available in Port Manager

*Nov 5 10:40:28.125: OSPF-1 ADJ Et0/1: Rcv pkt from 192.168.23.2, area 0.0.0.0 : src not on the same network

*Nov 5 10:40:31.354: OSPF-1 ADJ Et0/0: Rcv pkt from 192.168.24.2, area 0.0.0.0 : src not on the same network

*Nov 5 10:40:36.754: OSPF-1 ADJ Vl1: Rcv DBD from 192.168.0.1 seq 0x1FF1 opt 0x52 flag 0x7 len 32 mtu 1500 state INIT

*Nov 5 10:40:36.754: OSPF-1 ADJ Vl1: 2 Way Communication to 192.168.0.1, state 2WAY

*Nov 5 10:40:36.754: OSPF-1 ADJ Vl1: Neighbor change event

*Nov 5 10:40:36.754: OSPF-1 ADJ Vl1: DR/BDR election

*Nov 5 10:40:36.754: OSPF-1 ADJ Vl1: Elect BDR 10.11.0.102

*Nov 5 10:40:36.754: OSPF-1 ADJ Vl1: Elect DR 10.11.0.103

*Nov 5 10:40:36.754: OSPF-1 ADJ Vl1: DR: 10.11.0.103 (Id)

*Nov 5 10:40:36.754: OSPF-1 ADJ Vl1: BDR: 10.11.0.102 (Id)

*Nov 5 10:40:36.754: OSPF-1 ADJ Vl1: Nbr 192.168.0.1: Prepare dbase exchange

*Nov 5 10:40:36.754: OSPF-1 ADJ Vl1: Send DBD to 192.168.0.1 seq 0x334 opt 0x52 flag 0x7 len 32

*Nov 5 10:40:36.754: OSPF-1 ADJ Vl1: NBR Negotiation Done. We are the SLAVE

*Nov 5 10:40:36.754: OSPF-1 ADJ Vl1: Nbr 192.168.0.1: Summary list built, size 5

*Nov 5 10:40:36.754: OSPF-1 ADJ Vl1: Send DBD to 192.168.0.1 seq 0x1FF1 opt 0x52 flag 0x2 len 132

*Nov 5 10:40:36.754: OSPF-1 ADJ Vl1: Rcv DBD from 192.168.0.1 seq 0x1FF2 opt 0x52 flag 0x1 len 92 mtu 1500 state EXCHANGE

*Nov 5 10:40:36.754: OSPF-1 ADJ Vl1: Exchange Done with 192.168.0.1

*Nov 5 10:40:36.754: OSPF-1 ADJ Vl1: Send LS REQ to 192.168.0.1 length 36 LSA count 1

*Nov 5 10:40:36.754: OSPF-1 ADJ Vl1: Send DBD to 192.168.0.1 seq 0x1FF2 opt 0x52 flag 0x0 len 32

*Nov 5 10:40:36.754: OSPF-1 ADJ Vl1: Rcv LS UPD from 192.168.0.1 length 76 LSA count 1

*Nov 5 10:40:36.754: OSPF-1 ADJ Vl1: Synchronized with 192.168.0.1, state FULL

*Nov 5 10:40:36.754: %OSPF-5-ADJCHG: Process 1, Nbr 192.168.0.1 on Vlan1 from LOADING to FULL, Loading Done

*Nov 5 10:40:36.754: OSPF-1 ADJ Vl1: Rcv LS REQ from 192.168.0.1 length 72 LSA count 4

*Nov 5 10:40:37.243: ICMP: echo reply sent, src 192.168.255.2, dst 192.168.1.2, topology BASE, dscp 0 topoid 0

*Nov 5 10:40:37.244: ICMP: echo reply sent, src 192.168.255.2, dst 192.168.1.2, topology BASE, dscp 0 topoid 0

*Nov 5 10:40:37.394: OSPF-1 ADJ Et0/1: Rcv pkt from 192.168.23.2, area 0.0.0.0 : src not on the same network

*Nov 5 10:40:40.621: OSPF-1 ADJ Et0/0: Rcv pkt from 192.168.24.2, area 0.0.0.0 : src not on the same network

*Nov 5 10:40:41.452: OSPF-1 ADJ Vl1: Neighbor change event

*Nov 5 10:40:41.452: OSPF-1 ADJ Vl1: DR/BDR election

*Nov 5 10:40:41.452: OSPF-1 ADJ Vl1: Elect BDR 10.11.0.102

*Nov 5 10:40:41.453: OSPF-1 ADJ Vl1: Elect DR 10.11.0.103

*Nov 5 10:40:41.453: OSPF-1 ADJ Vl1: DR: 10.11.0.103 (Id)

*Nov 5 10:40:41.453: OSPF-1 ADJ Vl1: BDR: 10.11.0.102 (Id)

*Nov 5 10:40:41.453: OSPF-1 ADJ Vl1: Neighbor change event

*Nov 5 10:40:41.453: OSPF-1 ADJ Vl1: DR/BDR election

*Nov 5 10:40:41.453: OSPF-1 ADJ Vl1: Elect BDR 10.11.0.102

*Nov 5 10:40:41.453: OSPF-1 ADJ Vl1: Elect DR 10.11.0.103

*Nov 5 10:40:41.453: OSPF-1 ADJ Vl1: DR: 10.11.0.103 (Id)

*Nov 5 10:40:41.453: OSPF-1 ADJ Vl1: BDR: 10.11.0.102 (Id)

*Nov 5 10:40:47.172: OSPF-1 ADJ Et0/1: Rcv pkt from 192.168.23.2, area 0.0.0.0 : src not on the same network

!!!!Switch 3

SW3#show run

Building configuration...

Current configuration : 1272 bytes

! Last configuration change at 04:29:39 CST Sat Nov 5 2016

version 15.2

no service timestamps debug uptime

no service timestamps log uptime

no service password-encryption

service compress-config

hostname SW3

boot-start-marker

boot-end-marker

enable password cisco

no aaa new-model

clock timezone CST -6 0

no ip domain-lookup

ip cef

ipv6 multicast rpf use-bgp

no ipv6 cef

spanning-tree mode pvst

spanning-tree extend system-id

vlan internal allocation policy ascending

interface Ethernet0/0

shutdown

interface Ethernet0/1

shutdown

interface Ethernet0/2

switchport trunk encapsulation dot1q

switchport mode trunk

interface Ethernet0/3

shutdown

interface Ethernet1/0

shutdown

interface Ethernet1/1

switchport access vlan 1008

switchport mode access

interface Ethernet1/2

shutdown

interface Ethernet1/3

shutdown

interface Vlan1

ip address 192.168.0.3 255.255.255.0

ip ospf 1 area 0

interface Vlan1008

ip address 192.168.1.33 255.255.255.0

ip ospf 1 area 0

router ospf 1

ip forward-protocol nd

no ip http server

no ip http secure-server

control-plane

line con 0

exec-timeout 0 0

logging synchronous

line aux 0

line vty 0 4

password cisco

no login

end

SW3#show vtp status

VTP Version capable : 1 to 3

VTP version running : 3

VTP Domain Name : CISCO

VTP Pruning Mode : Disabled

VTP Traps Generation : Disabled

Device ID : aabb.cc00.6700

Feature VLAN:

--------------

VTP Operating Mode : Client

Number of existing VLANs : 9

Number of existing extended VLANs : 1

Maximum VLANs supported locally : 4096

Configuration Revision : 4

Primary ID : aabb.cc00.6500

Primary Description : SW1

MD5 digest : 0xE5 0x6D 0x8F 0x0B 0x12 0x2E 0xF7 0xF1

0x48 0xE9 0xF6 0x57 0x27 0x93 0x1E 0xB4

Feature MST:

--------------

VTP Operating Mode : Transparent

Feature UNKNOWN:

--------------

VTP Operating Mode : Transparent

SW3#show vlan

VLAN Name Status Ports

---- -------------------------------- --------- -------------------------------

1 default active Et0/0, Et0/1, Et0/3, Et1/0

Et1/2, Et1/3

2 VLAN0002 active

5 VLAN0005 active

55 VLAN0055 active

66 VLAN0066 active

1002 fddi-default act/unsup

1003 trcrf-default act/unsup

1004 fddinet-default act/unsup

1005 trbrf-default act/unsup

1008 VLAN1008 active Et1/1

VLAN Type SAID MTU Parent RingNo BridgeNo Stp BrdgMode Trans1 Trans2

---- ----- ---------- ----- ------ ------ -------- ---- -------- ------ ------

1 enet 100001 1500 - - - - - 0 0

2 enet 100002 1500 - - - - - 0 0

5 enet 100005 1500 - - - - - 0 0

55 enet 100055 1500 - - - - - 0 0

66 enet 100066 1500 - - - - - 0 0

1002 fddi 101002 1500 - - - - - 0 0

VLAN Type SAID MTU Parent RingNo BridgeNo Stp BrdgMode Trans1 Trans2

---- ----- ---------- ----- ------ ------ -------- ---- -------- ------ ------

1003 trcrf 101003 4472 1005 3276 - - srb 0 0

1004 fdnet 101004 1500 - - - ieee - 0 0

1005 trbrf 101005 4472 - - 15 ibm - 0 0

1008 enet 101008 1500 - - - - - 0 0

VLAN AREHops STEHops Backup CRF

---- ------- ------- ----------

1003 7 7 off

Primary Secondary Type Ports

------- --------- ----------------- ------------------------------------------

Again, your job is to diagnose & locate the source of the problem, please post your comments below & I will follow this up with a post detailing the solution in due course.

Friday 9 December 2016

CCIE RS Revision Series - 802.1D review questions around port allocations.

Some questions to tickle you on STP, the answers are at the bottom, let me know how you get on!

Given the topology below that is running 802.1D with all settings as default, please tell me:

1) What switch will be the Spanning-tree root bridge

a) Why will this be the root bridge?

2) What will be the BridgeID of all the BPDU's generated for VLAN 100?

a) What makes up this BridgeID value?

3)What ports on SW2 will be in the forwarding state?

a) What will the forwarding port roles be?

4) What port on SW4 will be the root port?

a) Why?

5) On Switch 4, which ports will be designated ports?

a) Why?

6) What ports will be blocked in the topology?

a) Why?

1) What switch will be the Spanning-tree root bridge (SW2)

a. Why will this be the root bridge? (It has the lowest MAC address, when all priories tie, this is the tiebreaker)

2) What will be the BridgeID of all the BPDU's generated for VLAN 100? (32868)

a. TWhat makes up this BridgeID value? (The BridgeID is the Priority+VLANID, where the default priority is 32768)

3) What ports on SW2 will be in the forwarding state? (All of them)

a. What will the forwarding port roles be? (all root bridge downstream ports are designated forwarding ports)

4) What port on SW4 will be the root port? (Port 1)

a. Why? (Root port is the one with the lowest cost to reach the root bridge, is there is a tie then it’s the lowest received BPDU, if there is still a tie then it’s the lowest received port priority, if there is still a tie it’s the lowest local port ID (where port 1 = 1, 2 = 2, and so on). Therefore the tie breaker here is the local port ID)

5) On Switch 4, which ports will be designated ports? (0, 3 & 4)

a. Why? (Designated Ports are calculated after Root Ports, of the two sides of the link they are calculated from the viewpoint of being on the link itself. Lets look at the SW1-Sw4 link. Here it’s a cost of 10 to reach the root via Sw1 or Sw4, therefore we look at the tiebreaker methods described in Q4a, the first item looks at the lowest BPDU where in this case SW4 has a lower one based on the MAC. Therefore SW4’s Port 0 is the DP & SW1’s Port 1 is the Alt blocked port)

6) What ports will be blocked in the topology? (SW1’s port 1, SW4’s Port 2 & SW3’s ports 1 & 2)

a. Why? (All opposite sides to Designated ports that are not Root facing Ports are set to Alternate Blocked ports, this is to stop loops)

Monday 9 February 2015

Using TCL to load new configs via ftp for ccie lab

Hi all,

Ok I regularly change my configs in my Lab, the only variable that changes is part of the filepath & each router uses its own hostname, eg:

For dmvpn lab

configure replace ftp://192.168.1.251//labs/dmvpn/r1.txt

configure replace ftp://192.168.1.251//labs/dmvpn/r2.txt

configure replace ftp://192.168.1.251//labs/dmvpn/r3.txt

For MPLS lab

configure replace ftp://192.168.1.251//labs/mpls/r1.txt

configure replace ftp://192.168.1.251//labs/mpls/r2.txt

configure replace ftp://192.168.1.251//labs/mpls/r3.txt

Currently is am pasting the string as follows in each device

“configure replace ftp://192.168.1.251//labs/mpls/r”

And then on each of the 20 devices I put the final bit [1.txt|2.txt|3.txt] etc & confirm this on all (the command requires confirmation via “yes”)

Yes this works, but I really am sick of going to every box to do this several times a day, so I have looked to try to make use of TCL to save time:

For my setup I have 20 CSR1000V & 1 windows VM running ftp, wireshark etc.

Base config

My base config on all boxes consists of an IP address, hostname & FTP credentials. After each lab I reset to this via:
configure replace flash:baseconfig.cfg
yes

Load lab

For my scrip lab scrips, all I now need to do is send the following syntax to all devices:

tclsh flash:labconfig.tcl MPLS.MP.BGP/

yes

TCL Script

So the script on each box is as follows (change the hostname variable on each device).

tclsh
puts [open flash:/labconfig.tcl w] {
set labname [lindex $argv 0]
set hostname "r9.txt"
typeahead "configure replace ftp://192.168.1.251//advanced.technology.labs/${labname}${hostname}"
}
tclquit

Outcome

Now when you run 'tclsh flash:labconfig.tcl MPLS.MP.BGP/' the CLI will return the output of 'configure replace ftp://192.168.1.251// labs/dmvpn/r9.txt' which allows us as uses to just sent one single command set to every box to load a new lab.

Granted, there probably is a better way to do this. But with the resources to hand this is all i manged to conjure up. Ultimately it works & hopefully will help another out there in the world!